The SailfishOS:Chum community repository configuration RPMs work on any SailfishOS release ≥ 3.1.0 and on all CPU-architectures.
Note that, before software can be build for a SailfishOS release at the SailfishOS-OBS, Jolla must create a corresponding "download on demand (DoD)" OBS-repository. It may take a little time after a new SailfishOS release is published before the corresponding "DoD" repository is being made available, during which installing or updating any software from the SailfishOS:Chum community repository on a device with the new SailfishOS release already installed does not work, because it cannot be compiled for this new SailfishOS release at the Sailfish-OBS, yet; consequently this is always the case for "closed beta (cBeta)" releases of SailfishOS.
But because this is a SailfishOS release independent noarch package, you can simply install a recent RPM file from OpenRepos (e.g., conveniently via Storeman), a recent RPM file from GitHub's releases page, manually select an RPM file built for any SailfishOS release or CPU architecture from chumrpm.netlify.app, or fully manually select an RPM file built for any SailfishOS release or CPU architecture from the SailfishOS-OBS.